As I said, the practice became prominent with the onset of Kali yuga. However, exact times and places can't be specified, at least I haven't seen such information.

Everyone who knows what varnasrama dharma is opposes jati dharma because it's a degraded system.

In the Gita Arjuna warns against degraded population (varna sankara) which is a product of Kali yuga before it actually happened.

Well, the tenth book of the Rig-Veda, where we have the first Varna ref., the Purusha Sukta, is thought by scholars to be no later than 1000 b.c.e., while Brhaspati's writings, the earliest to criticise the hierarchical birth-ghetto-izing jati dharma customs, is dated by some scholars as roughly 600 b.c.e. Since the Purusha Sukta makes no explicit ref. to the untouchables and only mentions four Varnas and does not explicitly reference birth or hierarchy, and since Brhaspati's reference suggests that jati dharma and the hereditary virus is in full swing by 600 b.c.e., that gives us a range of four centuries in which Varna becomes jati dharma. It may be that there is no way of further knowing just what else was going on during those first four centuries of the first millennium b.c.e. But it seems reasonable to assume that we can narrow down the time when jati dharma developed to those four hundred years.

Hey, we may be making some progress in answering some questions in this thread!

"Duality is bondage before moksa and wisdom after realization. The duality accepted for the purpose of bhakti is sweeter than even non-duality." (from mangalacarana to Advaitasiddhi sara sangraha by Madhusudana Sarasvati, former advaitin)

Among many other things, the chief conclusion in this article is that “Allele frequency differences between groups in India are larger than in Europe, reflecting strong founder effects whose signatures have been maintained for thousands of years owing to endogamy.” This article gives the details behind a genetic analysis, conducted this past decade, of the Indian population. It shows conclusively that the birth-based version of the caste system is rooted in the b.c.e.

What I find especially piquant here is that many who are tackling this history responsibly, genetic scientists included, are very careful to stipulate that they don’t view the birth-based version of this system as necessarily scriptural. The scriptural version of the system, as seen in the Purusha Sukta and the Bagavadgita, could still be read as oriented towards a non-hierarchical, non-blood-line version of varnas entirely, unlike the plain evidence in this article that what happened on the ground subsequent to that but way before the c.e. was the eventual formulation of a birth-based system.

Yet there are still those who are somehow offended at the blatant ancient evidence for birth-based caste-ism because they view it as somehow flouting Vedic beliefs, even though such practices are not explicitly sanctioned in the Vedic literature! No Vedic beliefs are being explicitly challenged in the growing consensus that there was ancient birth-based caste-ism. So why do some behave as if Vedic beliefs are being challenged? That is illogical.

Among many other things, the chief conclusion in this article is that “Allele frequency differences between groups in India are larger than in Europe, reflecting strong founder effects whose signatures have been maintained for thousands of years owing to endogamy.” This article gives the details behind a genetic analysis, conducted this past decade, of the Indian population. It shows conclusively that the birth-based version of the caste system is rooted in the b.c.e.

What I find especially piquant here is that many who are tackling this history responsibly, genetic scientists included, are very careful to stipulate that they don’t view the birth-based version of this system as necessarily scriptural. The scriptural version of the system, as seen in the Purusha Sukta and the Bagavadgita, could still be read as oriented towards a non-hierarchical, non-blood-line version of varnas entirely, unlike the plain evidence in this article that what happened on the ground subsequent to that but way before the c.e. was the eventual formulation of a birth-based system.

Yet there are still those who are somehow offended at the blatant ancient evidence for birth-based caste-ism because they view it as somehow flouting Vedic beliefs, even though such practices are not explicitly sanctioned in the Vedic literature! No Vedic beliefs are being explicitly challenged in the growing consensus that there was ancient birth-based caste-ism. So why do some behave as if Vedic beliefs are being challenged? That is illogical.

Walther

I'm sorry that a subsequent posting here, giving a useful URL for a translation of the Buddha Aganna Sutta in the Digha Nikaya, has been summarily pulled. I was hoping to address it at some point before the weekend. Why was it pulled?

The most interesting thing in that Sutta is that it provides a personal explanation, from Buddha, as to how he believes the birth-based caste system developed. However one takes that explanation, it's certainly pertinent to this discussion.

The Brahman was his (Purusha: primordial man - life itself) mouth, Rajanya (Kshatriya) was made from his hands, Vaishya from his thighs and Sudra from the feet. The supposed unequal status of castes is blamed on modern concept of feet being somehow inferior to the mouth. Whereas it clearly wasn't implied in the hymn. The feet, if anything are a solid foundation for Purusha; infact the meaning of the similie opens up when quoted in context of subsequent RV X.90.13 and RV X.90.14

Since Earth is revered as the mother in Sanatan Dharma, how could a comparison with Purusha's feet be deemed in anyway unequal or "lesser" than mouth. Therefore, the status of Sudra in Indian society is deemed as important spiritually as is the status of mother earth in the Cosmos. The similie of Earth and Sudra in fact to me connotes that included were people who were professionally connected to the land, ie. farmers.